package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 *
 * 秒杀下单
 * @author 小旭
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SEKILL_SCRIPT;

    static {
        SEKILL_SCRIPT = new DefaultRedisScript<>();
        SEKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SEKILL_SCRIPT.setResultType(Long.class);
    }

    //创建阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);

    //开启线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //表示在本类创建之后就立马执行以下代码
    @PostConstruct
    private void init(){
        //将VoucherOrderHandler中的run方法提交，然后执行
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    //take表示从队列中阻塞着取元素
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }

    IVoucherOrderService proxy;

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = UserHolder.getUser().getId();

        //获取锁对象
        // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();

        //判断是否获取锁成功
        if(!isLock){
            //失败，返回错误信息
            log.error("不允许重复下单");
            return;
        }

        try {
            //获取代理对象(事务)
            //注意此处代理对象也是通过ThreadLocal获取的，现在的异步线程获取不了
            //IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    /**
     *
     * @param voucherId
     * @return
     */
    @Override
    public Result seckillVoucher1(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SEKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0，代表没有购买资格
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }

        //2.2 为0，有购买资格，把下订单信息保存到阻塞队列
        //TODO 保存阻塞队列
        //3.创建订单
        VoucherOrder order = new VoucherOrder();
        //3.1订单id
        long orderId = redisIdWorker.nextId("order");
        order.setId(orderId);
        //3.2用户id
        order.setUserId(userId);
        //3.3代金券id
        order.setVoucherId(voucherId);
        //3.4初始化代理对象
         proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3.5放入阻塞队列
        orderTasks.add(order);
        //4.返回订单id
        return Result.ok(orderId);
    }

    @Override
    public Result seckillVoucher2(Long voucherId) {
        //1.根据id查询优惠卷库存信息
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀尚未开始");
        }
        //3.判断秒杀是否结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if(voucher.getStock()<1){
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();

        //获取锁对象
       // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
       RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();

        //判断是否获取锁成功
        if(!isLock){
            //失败，返回错误信息
            return Result.fail("不允许重复下单");
        }

        try {
            //获取代理对象(事务)
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }


    /**
     * 执行下单操作——一人一单
     * @param voucherId
     * @return
     */
    @Transactional
    public Result createVoucherOrder(Long voucherId) {
        //库存充足

        //一人一单
        Long userId = UserHolder.getUser().getId();
        //查询订单
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //判断是否存在
        if (count > 0) {
            return Result.fail("用户已经购买过一次");
        }

        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId).gt("stock", 0).
                        update();
        if (!success) {
            return Result.fail("库存不足");
        }

        //6.创建订单
        VoucherOrder order = new VoucherOrder();
        //6.1订单id
        long orderId = redisIdWorker.nextId("order");
        order.setId(orderId);
        //6.2用户id
        order.setUserId(userId);
        //6.3代金券id
        order.setVoucherId(voucherId);
        this.save(order);

        //7.返回订单id
        return Result.ok(orderId);
    }

    /**
     * 下单操作——一人一单
     * @param voucherOrder
     */
   @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //库存充足

        //一人一单
        Long userId = voucherOrder.getUserId();
        //查询订单
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //判断是否存在
        if (count > 0) {
            log.error("用户已经购买过一次");
            return;
        }

        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0).
                        update();
        if (!success) {
            log.error("库存不足");
            return;
        }
        //创建订单
        this.save(voucherOrder);

    }
}
